From the heights of Gibraltar you can see Africa about nine miles away to the south -- and gaze eastward on the seemingly endless Mediterranean that stretches 1,500 miles to Asia beyond. Mare Nostrum, "our sea," the Romans called the deep blue waters that allowed Rome to unite Asia, Africa and Europe for half a millennium under a single prosperous, globalized civilization.

Yet the Mediterranean has not always proved history's incubator of great civilizations -- Greek, Roman, Byzantine, Ottoman, Florentine and Venetian. Sometimes the ancient "Pillars of Hercules" at the narrow mouth of the Mediterranean here at Gibraltar marked not so much a gateway to progress and prosperity as a cultural and commercial cul-de-sac.

With the rise of the Ottoman Empire, and before the construction of the Suez Canal, the old classical city-state powerhouses in Italy and Greece faded from history, as the Mediterranean became more a museum than a catalyst of global change. In contrast, the Reformation and Enlightenment energized Northern European culture, safely distant from the exhausting frontline Mediterranean wars with Islam.

By the early 17th century, Northern Europeans more easily and safely reached the rich eastern markets of China and India by maritime routes around Africa. The discovery of the New World further shifted wealth and cultural dynamism out of the Mediterranean.

For a while the Mediterranean seemed to roar back after World War II. Huge deposits of petroleum and natural gas were found in North Africa. The Suez Canal was a shortcut to the newly opulent and strategically vital Persian Gulf. With the unification of Europe, and ongoing decolonization of Africa and the Middle East, there was the promise of a new, resource-rich, democratic and commercially interconnected Mediterranean.

Not now. The Arab Spring has brought chaos to almost all of North Africa. The bloodbath in Syria threatens to escalate into something like the Spanish Civil War -- sucking in Lebanese militias, Iranian mercenaries, Turkey, the Sunni sheikdoms, Israel and the Palestinians, along with surrogate arms suppliers like China, Europe, Russia and the United States.

The economies of the Islamic rim of the Mediterranean are in shambles. But then so is the southern flank of the European Union, as Greece, Italy, Portugal and Spain haggle for subsidies and loans from an increasingly fed-up Northern Europe. New gas and oil finds in North America, China and Africa may soon make both Mediterranean supplies and Suez passage to the Persian Gulf irrelevant for a billion energy consumers.

A shrinking and aging Europe keeps drawing in young Muslim immigrants from the Middle East and North Africa. They want out of their impoverished Islamic homelands but are being consumed by, rather than enriching, the wealthier European societies that they are drawn to like moths to a flame. The recent rioting in Sweden, the gruesome near-beheading of a soldier in London and periodic unrest in the French suburbs all remind us that the Mediterranean is not a shared postmodern vacation getaway. Instead it is increasingly a stagnant premodern pond of religious, political and economic tensions.

Unrest in the West Bank, Gaza, Cyprus, Syria, Libya and Egypt could at any moment spark violence that cuts across religious, racial and political fault lines. Yet otherwise, these tired hotspots are immaterial to a world that from Shanghai, Mumbai and Seoul to Palo Alto, Houston, London and Frankfurt is creating vast new wealth, technologies and consumer goods -- without much of a nod to Mediterranean science or innovation.

The old strategic fortresses at Cyprus, Crete, Sicily, Malta and Gibraltar are becoming inconsequential, as the United States pivots to Asia. The Cold War is long over. Europe has all but disarmed. Meanwhile, the societies on the southern and eastern shores of the Mediterranean are coming apart at the seams.

It is hard to find a robust free-market economy anywhere in the Mediterranean these days. Instead, European socialism, Arab statism and Islamic terrorism in various ways are retarding commerce and growth. Mediterranean tourism -- with visitors gazing at ancient rather than modern wonders -- is more profitable than manufacturing.

Will the Mediterranean world rebound again? History is cyclical not linear, and the region's favorable climate and opportune geography suggest that it could.

Before we see another Mediterranean renaissance, constitutional government would have to sweep the Muslim world. The fossilized bureaucracy of the European Union would have to radically reform or disappear. A new generation of Michelangelos and da Vincis would have to believe that they could think, say and write whatever they wished -- in a climate of economic confidence, prosperity and security.

Unfortunately, the culture of the Mediterranean is reverting to its stagnant 18th-century past rather than leading the 21st century.